College of Construction Engineering, Jilin University, Changchun 130026, China

In construction of the main pier of Songhua River super large bridge channel in Lanqi, the bored pile with 2 m in diameter by 50 m long is used as base for self-balancing testing the bearing capacity of pile foundation. Collecting the experimental data of 5-1#, 6-2#, 6-3# test piles, the authors analyze the bearing characteristics and load transfermechanism of large-diameter and mid-long bored piles and the influencing factors on bearing characteristics, in the aspects of load-settlement relationship, distribution of side friction of pile, pile-soil relative displacement and performance of tip resistance. The results show that ultimate loads of 5-1#, 6-2#, 6-3# are 68 917 kN, 62 316 kN and 75 234 kN, respectively.